Did anyone try the Hornady Light Magnum 7x57 139grain SST factory ammo back in the day?

[HandB]

I have been experimenting with the Hornady 139grain SST bullets in my 7x57 and they shoot fairly accurately at modest velocities (around 2,400fps from a 24" barrel). To do justice to the streamlined design of the bullets I should really push them a bit faster and in my research have found out that Hornady used to make what they called a Light Magnum 7x57 139grain SST factory loading that they claimed would produce a muzzle velocity 2,830 fps. That muzzle velocity sounds a bit optimistic to me. Can anyone recall using this cartridge back in the day and whether it realistically did produce that official muzzle velocity? Also was it an accurate load?

 

[Heym SR20]

The original Rigby 275 High Velocity ammo a 140 gn bullet at a MV of 2,800 fps. And this sort of velocity is pretty easily achieved in 7x57. Most factory 7mm-08 is 2800 fps with a 140gn bullet and that has less case capacity than the 7 x57.

Most data and ammo is somewhat anaemic as they are number of old rifles that may not stand up to high pressures.

 

[Heym SR20]

Lots of useful info here

7x57

And on the various 7mm SST bullets

7mm - Hornady SST

7mm SST terminal performance

www.ballisticstudies.com

 

[HandB]

Thank you!

 

[Wilf102]

Yes. I have used them on roe. Like strapping a hand grenade to the side of the deer. Haven’t used SST since.

 

[Sika98k]

Rigby quote their 140 grain load using Nosler Partitions as doing 2800fps.

 

[NP435]

I am getting 2750 out of a 22 inch 7x57 Nosler 140 Ballistic tip over H4831sc.

 

[Dorset Shakari]

Very impressive terminal effect using that bullet through my 7x64 at around 2800 fps.

 

[BWH]

I used them in the past. Chrono said 2750 I think, maybe slighty less but definately not as advertised. Used on red hinds. Worked reasonably well.

 

[HandB]

Thanks very much everyone - it seems I need to let the cartridge stretch its legs a bit more.